Absorbent articles for personal hygiene, such as disposable baby diapers, training pants for toddlers or adult incontinence undergarments, are designed to absorb and contain body exudates, in particular urine. These absorbent articles comprise several layers providing different functions, typically including a topsheet, a backsheet and in-between an absorbent core, among other layers.
The absorbent core should be able to absorb and retain the exudates for a prolonged amount of time, for example overnight for a diaper, minimize re-wet to keep the wearer dry, and avoid soiling of clothes or bed sheets. The majority of currently marketed absorbent cores comprise as absorbent material a blend of comminuted wood pulp cellulose fibers with superabsorbent polymers (SAP) in particulate form, also called absorbent gelling materials (AGM), see for example U.S. Pat. No. 5,151,092 (Buell).
Absorbent articles having a core consisting essentially of SAP as absorbent material (so called “airfelt-free” cores) have also been proposed. WO95/11652 (Tanzer) discloses absorbent articles which include superabsorbent material located in discrete pockets. US2002095127 (Fish) discloses a laminate structure that is formed from a first substrate, a second substrate, and discrete regions of particles sandwiched therebetween. In particular, the first and second substrates are bonded together at certain portions such that bonded portions and unbonded portions are formed. The unbonded portions form pockets that contain the particles. The pockets have a length-to-width ratio of greater than about 2. WO2008/155699 (Hundorf) discloses an absorbent core comprising first and second absorbent layers each comprising an absorbent particulate polymer material such that the absorbent particulate polymer material is substantially continuously distributed across an absorbent particulate polymer material area. WO2012/170778 (Rosati et al., see also WO2012/170779, WO2012/170781 and WO2012/170808) discloses absorbent structures that comprise superabsorbent polymers, optionally a cellulosic material, and at least a pair of substantially longitudinally extending absorbent material free zones that can form channels as the absorbent structure absorb a fluid.
While the previously proposed absorbent cores can provide good absorbency capacity, there is a continuous need to improve the properties of cores in a cost effective manner. In particular there is a continuous need to improve wearing comfort, increase production speed and reduce raw material usage while keeping optimal fluid management properties.